These latest miraculous gains by Thibaudeau are a little contradictory because, while he’s said repeatedly on their forum that he could get much bigger if he wanted to, he’s also been saying that he doesn’t want to/can’t because of health issues (and I believe he also said that he only took steroids experiementally for a little while when he was a teenager). He clearly must have changed his mind, however, because he’s just claimed to have gained more muscle in 6 weeks than many drug-free bodybuilders of his stature gain in a lifetime of training. He’s doing very well – he’s now carrying over 40 pounds more muscle than the world’s best drug-free bodybuilding champions of his height (which is also well over twice as much muscle as they’ve managed to build).
The structure of cyclocreatine is fairly flat (planar), which aids in passive diffusion across membranes. It has been used with success in an animal study, where mice suffered from a SLC6A8 (creatine transporter at the blood brain barrier) deficiency, which is not responsive to standard creatine supplementation.  This study failed to report increases in creatine stores in the brain, but noted a reduction of mental retardation associated with increased cyclocreatine and phosphorylated cyclocreatine storages.  As demonstrated by this animal study and previous ones, cyclocreatine is bioactive after oral ingestion   and may merely be a creatine mimetic, able to phosphorylate ADP via the creatine kinase system.